Burglar-alarm.



L. M. PRATT.

BURGLAR ALARM. APPLICATION FILED APR. 8, 1913.

1,096,001. Patented May 5-, 1914.

, b nnnnnnnnnn Witnesses Inventor 4 v by I I I Attorneys s'ra'rss NT f T@ LEWIS IVI. PRATT, OF OKLAHOMA, OKLAHOMA, ASSIGNOB TO CHARLES ECKES, OF OKLAHOMA, OKLAHOMA.

BURGLAR-A LARM.

To all whom it may concern:

Be it known that I, LEwIs M. PRATT, a citizen of the United States, residing at Oklahoma, in the county of Oklahoma and State of Oklahoma, have invented a new and useful Burglar-Alarm, of which the following is a specification.

This invention relates to a burglar alarm.

An object of the present invention is to provide a burglar alarm which can be conveniently attached to any door or window without marring the same.

A further object is to provide a burglar alarm operated by the opening of a door or window, the alarm being given by the exploding of a cap.

A further object is to provide a burglar alarm which may be set or unset from either side of the door or window to which the alarm is secured.

Another object is to provide a burglar alarm which may be set or unset by means of a key.

With the foregoing and other objects in view which will appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed, can be made within the scope of what is claimed, without departing from the spirit of the invention.

In the drawings accompanying this specification and forming a part thereof, the preferable form of my invention is illustrated, in which Figure 1 is a view in elevation showing a portion of a door and casin with my improved burglar alarm secured thereto. Fig. 2 is a vertical cross sectional view thereof. Fig. 3 is a vertical cross sectional view illustrating the actuating mechanism. Fig. 4 is an enlarged horizontal sectional view of the casing illustrating a somewhat modified form of the device. Fig. 5 illustrates a key for setting or unsetting the alarm. Fig. 6 illustrates a somewhat modified form.

Referring to the drawings in which similar reference numerals designate corresponding parts throughout the several views, 1 represents a door and 2 the casing, the said door and casing being of the ordinary construction and serve merely to illustrate the manner in which my improved burglar Specification of Letters Patent.

Application filed April 8, 1913.

Serial No. 759,812.

alarm may be attached to a door. The burglar alarm may'also be attached to a window in somewhat the same manner as it is secured to a door.

In order that the alarm may be detachably secured to a door casing and may be readily detached therefrom, the clamp 4 is illustrated and serves as means whereby the alarm may be temporarily secured to a casmg without marring or defacing the same. Clamp 4t comp-rises a metallic strap 5 the forward end of which is bent inward as at 6 to engage the inner portion of the casing and the rear end of the said strip is bent inward as at 7 and a thumb screw 8 threadedly engages the same, which thumb screw is adapted to engage the outer portion of the casing and to secure the said clamp to the casmg.

The alarm comprises a flat hollow casing 9 of regular contour and preferably formed of metal. The casing 9 comprises the side walls 10, the front wall 11 and the rear wall 12, the said terms being merely relative in order to more clearly describe the construction. Pivotally mounted to the side walls 10 of the alarm casing is what is termed a hammer 13, the said hammer be ing formed of two strands of wire as illus trated in Fig. 2 of the drawings, the lower ends of which are bent outward and in alinement and are ournaled within the side wall apertures 11. The upper extremity of the hammer is provided with the rearwardly projecting knob 15 which is adapted to contact with a cap holding or retaining member 16, and a safety plate 15 is secured to the upper extremity of the said hammer and is to prevent danger of fire, due to the eX ploding of the cap. The said cap holding member is illustrated as formed of a spring 16 which is rigidly secured to the lower portion ofthe rear wall 12. A cap containing an'explosive, such as dynamite is adapted to be placed between the spring 16 and the wall 12 of the casing andwill be held securely in place and in such a position as to receive the force or pressure exerted by the hammer 13 when the same is released and comes forcibly into contact with the spring 16.

Rigidly secured to the front wall 11 of the casing is a bow spring member 17 which engages the lower pivoted end of the hammer 13 and is adapted to actuate the same somewhat Patented May 5, rate. I

similar to the manner in which an ordinary gun hammer is actuated. In order to protitle a trigger for the holding and releasing of the said hammer, the member 18 is pivotally secured to the upper portion 15 of the hammer 1.3 and the same extends through an apt-u'ture 19 formed in the front wall of the casing. The trigger 18 is provided with a portion which is bent upon itself as at and forms thereby a short end or catch 21 which is adapted to contact with. the side walls adjacent the aperture 19 and to hold the trigger in the position as illustrated in Fig. 1 of the drawings. The aperture 19 is sufficiently large to allow the portions 18 and 20 to readily pass therethrough when the end 21 is brought from engagement with the sides of the aperture 19.

In order to provide means for the setting of the alarm, by which is meant the bringing of the hammer into the position as illustrated in Fig. 1 of the drawings and then introducing an explosive cap beneath the spring or cap holding member 16, keyholeshaped openings 22 are provided in the side walls of the alarm casing and juxtaposed the hammer 13. The key as illustrated in Fig. 5 of the drawings is of the usual type and is provided with a somewhat elongated lug 23 which is adapted to contact with the hammer 13 and act as a lever thereagainst. One portion of the eye of the key is bent outward as at 2d the purpose of which is to provide means which may extend through an aperture 25 in the end wall 12 of the easing and contact with the spring or cap holding member 16, to force the same away from the wall 12 which allows a cap to be readily inserted therebetween. The modified form as illustrated in Fig. 6, provides a projecting knob 27 secured to or formed integral with the said cap holding member 16 whereby the same may be swung inwardly for the insertion of the cap without the use of the key as just described.

Fig. 1 of the drawings illustrates the burglar alarm securely held by the clamp t to a door casing and adjacent the hinge portion thereof. The manner in which the alarm 0perates when so secured, is as follows :The key as illustrated in Fig. 5, is inserted within the keyholes 22 and by a suitable rotation thereof, the portion or lug 23 is brought to contact with the hammer 13 and the same is rotated about its trunnion which extends through the aperture 14 and the hammer is brought to the position as illustrated in Fig. 1, of the drawings, and by reason of a strip 26 which is cut from the side wall of the easing, the said strip acting in the capacity of a spring member, it being noted that as illustrated in Fig. 4c, the spring member 26 may be a separate piece rigidly secured to the side wall of the casing as at 28 in Fig. 4: of the drawings. The outer extremity of the trigger 18 will be pressed against the side walls of the aperture 19 until such time as the portion 21 thereof has cleared the outer portion of the said aperture and the trigger 18 will then be sprung into the position as illustrated. in Figs. 2 and t of the drawings. The key may then be withdrawn from the said casing and the trigger will remain in set position. The portion 24: of the key is then inserted within the aperture 25 and an explosive cap inserted between the cap holding member 16 and the wall 12 which have been forced apart by means of the said hey. When the door 1 is now opened, the side thereof will come into Contact with the outer extremity of the trigger 18 and will move the same laterally until the portion 21 clears the side walls of the opening 19 at which time, by re. son of the spring 17 the hammer will be thrown violently against the cap holding member 16 and the same exploded. The outer portion of the trigger 18 when the hammer is in the position as illustrated in Fig. 3 of the drawings is out of the way of the door and will not be injured by any movement thereof. The burglar alarm herein described may be secured to a window and such a construction is illustrated in Fig. 4 of the drawings in which the window sash is illustrated at 29 and to which is rigidly se cured a wiping arm 30, the same being bent at an angle as at 31 and is adapted to contact with and release the trigger of the burglar alarm when the window is raised.

The many various uses to which a device of this character may be placed will be ap parent, among which may be mentioned the positioning of the casing upon a door with the key-hole shaped openings of the casing in alinement with the key-hole opening of the door, and although this is not illustrated in the present drawings it is thought that the same is not necessary. lVith the casing so positioned it allows the cap exploding mechanism to be set or unset from either side of the door by the use of a proper key.

Having thus described the invention, what I claim to be new and original with me is 1. In a device of the class described. a casing, a spring secured to one end thereof adapted to hold an explosive cap therehehind, an aperture disposed adjacent said spring. means extending through said aper ture adapted to contact with said spring to move the same to allow an explosive cap to be inserted therein, a. hammer rotatably mounted within said casing, actuating means for said hammer, and a trigger secured to said hammer.

2. In a device of the class described. a casing, a spring actuated hammer disposed therein, a trigger secured to said hammer and adapted to hold the same in a set condition, cap holding means, and a safety plate disposed at the upper extremity of said hammer adapted to extend over the cap holding means to provide a guard therefor during the exploding of the cap.

3. In a device of the class described, the combination of a casing having an opening, a cap exploding mechanism in the casing including a trigger extending through said opening, means for holding the trigger continuously in contact With a side Wall of said opening, said casing provided With a keyhole shaped opening, and a key removably and rotatably positioned Within the keyhole shaped opening, said key contacting With the cap exploding mechanism, the rotation of said key moving the cap exploding mechanism to a set position.

In testimony that I claim the foregoing as my own, I have hereto afiixed my signature in the presence of two Witnesses.

LEWIS M. PRATT.

Witnesses CHARLES Eoxns, BLANCH BLIOKENSTAFF.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

